4.1 D IVER C OMMUNICATIONS The audio path for the signals received from a diver is divers Headset to Unscrambler Terminals to Audio Module PCB to Mixer PCB to the DSP PCB (channel 3). After the audio has been unscrambled it is then routed to the supervisor headset and speaker. If divers round robin is active the signal will also be routed to the headsets of the other divers. Signals are routed within the unscrambler to the audio module PCB’s where the signals are amplified depending on the position of the volume controls. Each channel has its own dedicated audio module. The audio signals are mixed together in the mixing PCB before being processed through the DSP to be digitally unscrambled (only channel 3 is unscrambled. The diver audio is then routed back to the audio output connectors, speakers or supervisor headset. The divers can talk to the supervisor and the diver microphone outputs will always be audible at the surface end. The diver microphone output has a minimum listening level so the volume of a diver cannot be turned down so low that they cannot be heard. When diver round robin is switched on channels 1, 2 and 3 are able to communicate with each other. Each channel has its own dedicated volume control for diver round robin. The diver to supervisor volume can be adjusted for each channel individually via the channels volume control or the volume of all channels to the supervisor can be adjusted using the master volume dial.